A better idea to annoy the Norks
Extensive research, carried out on crowded commuter trains plagued by tinny nose emanating from leaky earbuds, strongly suggests that the optimum strategy for annoying the neighbours would not be a small number of high-powered speaker arrays, but rather a swarm of a million micro-drones equipped with milliwatt-class transducers featuring high-pass filters set at 5kHz. Effects on the subject include irritation, loss of concentration, and feelings of helplessness. Oh, and homicidal rage - probably unfortunately, in the case of North Korea.